The invention relates to a handling device for drill rods for deep boreholes, e.g. for crude oil and natural gas exploration. The term “pipe handler” has become established in technical terminology for such a handling device, and accordingly the term “pipe handler” is used in the following synonymously with the expression “handling unit for drill rods”.
A pipe handler is part of a so-called top drive, that is to say the vertically moving drive unit in the mast of a drilling rig which sets the drill rods into rotational movement for the drilling process by means of a drive assembly, usually an electric motor, which is contained within the drive unit. For this purpose, the top drive is divided into a fixed and a rotatable unit. The fixed unit comprises the drive assembly. The element which can be rotated by the drive assembly is the pipe handler. The units of the pipe handler are supplied via a rotary hydraulic union between fixed and rotatable part of the top drive, namely in that a pressurized hydraulic fluid is applied to the pressure cylinder and the like, for example to move so-called elevator brackets or to activate holding tongs for drill rods provided on a so-called torque arm.
A swivel movement capability is provided especially for the elevator brackets of the pipe handler, as the elevator brackets (usually two) carry a so-called rod elevator at the ends thereof in order to remove drill rod elements from a store and to feed the removed drill rod element to the holding tongs at the end of the torque arm.
A certain quantity of drill rod elements is normally held available vertically next to or on the mast of the drilling rig for storage purposes, and a so-called fingerboard, which is located on the mast in the region of the top end of the stored drill rod elements, is provided for this purpose. An additional or alternative storage position for at least one drill rod element is the so-called mouse hole. Up to now, the removal of drill rod elements from their storage position and also in the opposite direction, namely the depositing of drill rod elements in a storage position, has been carried out under manual control. For this purpose, the top drive is moved to an appropriate vertical position in the mast which enables drill rod elements to be removed or deposited. As soon as the top drive is in this position, the or each elevator bracket is swiveled and a drill rod element is collected or deposited by means of the rod elevator.
With regard to a problem which existed up to that point that essential control operations for initiating and concluding such handling processes were left substantially to the attention of the operating personnel, devices and methods with which a fully automatic monitoring of the pipe handler and/or of the top drive with pipe handler is possible have been proposed in
DE 10 2009 039 022 A. In particular, a possible way of detecting a position of the at least one elevator bracket is specified. DE 10 2009 039 022 A is expressly included in the disclosure content of the present description, e.g. with regard to the electrical and hydraulic supply and control of the top drive explained therein. Further technical background of the relevant prior art, albeit only general in scope, can be seen from U.S. Pat. No. 4,326,745 and U.S. Pat. No. 4,800,968.